Advanced platelet-rich fibrin: a new concept for cell-based tissue engineering by means of inflammatory cells

Preparation, characterization and evaluation of a new film based on chitosan, arginine and gold nanoparticle derivatives for wound-healing efficacy

It is well-known that the combination of polymers and nanoparticles (NPs) provides optimised wound dressing and accelerates wound healing. The knowledge about the structure and properties of these materials is of critical importance in biological processes related to wound healing. In this study, we prepared a chitosan (CS) film modified with arginine (Arg) and gold NPs (AuNPs) and investigated its effectiveness as a dressing material for wound healing. Fourier-transform infrared spectroscopy (FTIR) confirmed that Arg was successfully grafted on CS. The resultant CS-Arg/AuNP film was then characterised by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The modification of Arg and AuNPs improved the hydrophilicity, mechanical strength and antibacterial properties of the film, which in turn provided an enhanced ideal environment for cell adhesion and proliferation. Cell Counting Kit-8 (CCK-8) was used to demonstrate the survival rate. Furthermore, the proteins involved in wound healing were evaluated qualitatively and quantitatively by immunofluorescence and western blotting, respectively. The skin defect models used for the in vivo studies revealed that the CS-Arg/AuNP dressing accelerated wound closure, re-epithelialization and collagen deposition. Our cumulative findings support the feasibility of using the proposed film as a promising candidate for tissue engineering of the skin in the near future.

It is well-known that the combination of polymers and nanoparticles (NPs) provides optimised wound dressing and accelerates wound healing.

Platelet-derived bio-products: Classification update, applications, concerns and new perspectives

Platelet derived bio-products in the form of platelet rich plasma, plasma rich in growth factors, or plasma-free platelet releasates, are being studied worldwide with the aim of proving their efficacy in tissue regeneration within many different clinical areas, such as traumatology, maxillofacial surgery, ophthalmology, dermatology and otorhinolaryngology, amongst others. The current lack of consensus in the preparation method and application form, or in the quality assessment of each bio-product, precludes adequate interpretation of the relevance of reported clinical outcomes, and, while many in clinicians are very positive about them, many are sceptic. Relevant aspects of these products are considered to propose a classification nomenclature which would aid a comprehensive comparison of clinical outcomes of bio-products of the same characteristics. Finally, the uses of platelet-derived bio-products in in vitro culture (for cell therapy purposes) as a substitute of animal-origin sera, and other future perspectives of applications of platelet-derived bio-products are discussed.

Assessment of platelet-rich fibrin in the maintenance and recovery of cell viability of the periodontal ligament

This study analyzed the efficacy of autologous platelet-rich fibrin (PRF) in maintaining and recovering cell viability of the periodontal ligament (PDL). The PDL cells were isolated from 45 extracted teeth randomly distributed among 6 groups: 5 min, 1 h, 2 h, PRF 30 min, PRF 1 h and PRF 2 h. In the groups 5 min, 1 h and 2 h (n = 5), the teeth were kept dry in extra-alveolar times of 5 min, 1 h and 2 h respectively. The teeth of the groups PRF 30 min, PRF 1 h and PRF 2 h (n = 10) were kept dry at extra-alveolar times of 30 min, 1 and 2 h followed by immersion in PRF for 45 min. PDL cells were isolated by enzymatic digestion with type II collagenase and dispase, counted and analyzed for viability with Trypan blue vital dye in Neubauer chamber. The variables total number of cells and cell viability demonstrated that in the 5 min, 1 h and 2 h groups there was a decrease after the extra-alveolar dry times of 1 and 2 h. In comparison with the total number of cells, group 1 h, considered immediate reimplantation, did not present statistical difference when compared to the groups PRF 30 min, PRF 1 h and 2 h, a result that demonstrates that PRF assists in cell maintenance and recovery. PRF provided increased cell viability in relation to the different dry extra-alveolar times analyzed (p < 0.001). Autologous PRF presented effectiveness in maintaining and recovering PDL cells from extracted teeth and kept dry for up to 2 h.

Platelet-Rich Fibrin as a Bone Graft Material in Oral and Maxillofacial Bone Regeneration: Classification and Summary for Better Application

Platelet-rich fibrin (PRF) is an autologous platelet concentrate that consists of cytokines, platelets, leukocytes, and circulating stem cells. It has been considered to be effective in bone regeneration and is mainly used for oral and maxillofacial bone. Although currently the use of PRF is thought to support alveolar ridge preservation, there is a lack of evidence regarding the application of PRF in osteogenesis. In this paper, we will provide examples of PRF application, and we will also summarize different measures to improve the properties of PRF for achieving better osteogenesis. The effect of PRF as a bone graft material on osteogenesis based on laboratory investigations, animal tests, and clinical evaluations is first reviewed here. In vitro, PRF was able to stimulate cell proliferation, differentiation, migration, mineralization, and osteogenesis-related gene expression. Preclinical and clinical trials suggested that PRF alone may have a limited effect. To enlighten researchers, modified PRF graft materials are further reviewed, including PRF combined with other bone graft materials, PRF combined with drugs, and a new-type PRF. Finally, we will summarize the common shortcomings in the application of PRF that probably lead to application failure. Future scientists should avoid or solve these problems to achieve better regeneration.

Biologization of Collagen-Based Biomaterials Using Liquid-Platelet-Rich Fibrin: New Insights into Clinically Applicable Tissue Engineering

Platelet-rich fibrin (PRF) is a blood concentrate derived from venous blood that is processed without anticoagulants by a one-step centrifugation process. This three-dimensional scaffold contains inflammatory cells and plasma proteins entrapped in a fibrin matrix. Liquid-PRF was developed based on the previously described low-speed centrifuge concept (LSCC), which allowed the introduction of a liquid-PRF formulation of fibrinogen and thrombin prior to its conversion to fibrin. Liquid-PRF was introduced to meet the clinical demand for combination with biomaterials in a clinically applicable and easy-to-use way. The aim of the present study was to evaluate, ex vivo, the interaction of the liquid-PRF constituents with five different collagen biomaterials by histological analyses. The results first demonstrated that large variability existed between the biomaterials investigated. Liquid-PRF was able to completely invade Mucograft^® (MG; Geistlich Biomaterials, Wolhusen, Switzerland) and to partly invade Bio-Gide^® (BG; Geistlich Biomaterials, Wolhusen, Switzerland) and Mucoderm^® (MD; Botiss Biomaterials, Berlin, Germany), and Collprotect^® (CP; Botiss Biomaterials, Berlin, Germany) showed only a superficial interaction. The BEGO^® collagen membrane (BCM; BEGO Implant Systems) appeared to be completely free of liquid-PRF. These results were confirmed by the different cellular penetration and liquid-PRF absorption coefficient (PAC) values of the evaluated membranes. The present study demonstrates a system for loading biomaterials with a complex autologous cell system (liquid-PRF) in a relatively short period of time and in a clinically relevant manner. The combination of biomaterials with liquid-PRF may be clinically utilized to enhance the bioactivity of collagen-based biomaterials and may act as a biomaterial-based growth factor delivery system.

A novel method for harvesting concentrated platelet-rich fibrin (C-PRF) with a 10-fold increase in platelet and leukocyte yields

BACKGROUND AND OBJECTIVES

Liquid platelet rich fibrin (PRF; often referred to as injectable PRF) has been utilized as an injectable formulation of PRF that is capable of stimulating tissue regeneration. Our research group recently found that following standard L-PRF protocols (2700 RPM for 12 min), a massive increase in platelets and leukocytes was observed directly within the buffy-coat layer directly above the red blood cell layer. The purpose of this study was to develop a novel harvesting technique to isolate liquid PRF directly from this buffy coat layer and to compare this technique to standard i-PRF.

MATERIALS AND METHODS

Standard high g-force L-PRF and low g-force i-PRF protocols were utilized to separate blood layers. Above the red blood corpuscle layer, sequential 100-μL layers of plasma were harvested (12 layers total; i.e., 1.2 mL, which represents the total i-PRF volume), and 3 layers (3 × 100 μL) were harvested from the red blood cell layer to quantify blood cells. Each layer was then sent for complete blood count (CBC) analysis, and the cell numbers were quantified including red blood cells, leukocytes, neutrophils, lymphocytes, monocytes, and platelets. The liquid PRF that was directly collected from the buffy-coat layer following L-PRF protocols was referred to as concentrated PRF (C-PRF).

RESULTS

The i-PRF protocol typically yielded a 2- to 3-fold increase in platelets and a l.5-fold increase in leukocyte concentration from the 1- to 1.2-mL plasma layer compared to baseline concentrations in whole blood. While almost no cells were found in the first 4-mL layer of L-PRF, a massive accumulation of platelets and leukocytes was found directly within the buffy coat layer demonstrating extremely high concentrations of cells in this 0.3-0.5-mL layer (~ 20-fold increases). We therefore proposed harvesting this 0.3- to 0.5-mL layer directly above the red blood cell corpuscle layer as liquid C-PRF. In general, i-PRF was able to increase platelet numbers by ~ 250%, whereas a 1200-1700% increase in platelet numbers could easily be achieved by harvesting this 0.3-0.5 mL of C-PRF (total platelet concentrations of > 2000-3000 × 10⁹ cells/L).

CONCLUSION

While conventional i-PRF protocols increase platelet yield by 2-3-fold and leukocyte yield by 50%, we convincingly demonstrated the ability to concentrate platelets and leukocytes over 10-fold by harvesting the 0.3-0.5 mL of C-PRF within the buffy coat following L-PRF protocols.

CLINICAL RELEVANCE

Previous studies have demonstrated only a slight increase in platelet and leukocyte concentrations in i-PRF. The present study described a novel harvesting technique with over a 10-fold increase in platelets and leukocytes that can be further utilized for tissue regeneration.

[Research progress on platelet-rich fibrin derivatives]

Platelet-rich plasma and platelet-rich fibrin (PRF) are widely used in the field of stomatology. Advance-ments in preparation techniques and basic research have enabled the use of PRF derivatives in oral clinical applications. The evolution, preparation techniques, biological properties, and medical research progress of PRF derivatives are reviewed in this paper.

Fluid platelet-rich fibrin stimulates greater dermal skin fibroblast cell migration, proliferation, and collagen synthesis when compared to platelet-rich plasma

BACKGROUND

Regenerative therapies in the field of facial aesthetics have become a growing field of interest with many recent advancements made over the past decade to meet the growing worldwide demand. While first versions of platelet-derived concentrates were formulated with anticoagulants (PRP), recent modifications to centrifugation speeds and times have permitted the development of a liquid platelet-rich fibrin (fluid-PRF) without use of anticoagulants.

OBJECTIVE

To compare this entirely natural platelet concentrate (fluid-PRF) to formally utilized PRP on skin cell behavior and regeneration.

METHODS

Dermal skin fibroblast was cultivated with either fluid-PRF or PRP and investigated for their ability to promote/influence cell viability, migration, spreading, proliferation, and mRNA levels of known mediators of dermal biology including PDGF, TGF-beta, and fibronectin.

RESULTS

All platelet concentrates were nontoxic to cells demonstrating high cell survival. Skin fibroblasts migrated over 350% more in fluid-PRF when compared to control and PRP (200% increase). Fluid-PRF also significantly induced greater cell proliferation at 5 days. While both PRP and fluid-PRF induced significantly elevated cell mRNA levels of PDGF, it was observed that TGF-beta, collagen 1, and fibronectin mRNA levels were all significantly highest in the fluid-PRF group. Lastly, fluid-PRF demonstrated a significantly greater ability to induce collagen matrix synthesis when compared to PRP.

CONCLUSION

The findings from the present study demonstrate greater regenerative potential of fluid-PRF on human skin fibroblasts. Future clinical use of fluid-PRF in the field of facial aesthetics is necessary to further evaluate the potential advantages of anticoagulant removal from platelet concentrates.

New Frontiers in Skin Rejuvenation, Including Stem Cells and Autologous Therapies

One of the greatest challenges in the progression of aesthetic medicine lies in providing treatments with long-term results that are also minimally invasive and safe. Keeping up with this demand are developments in autologous therapies such as adipose-derived stem cells, stromal vascular fraction, microfat, nanofat, and platelet therapies, which are being shown to deliver satisfactory results. Innovations in more traditional cosmetic therapies, such as botulinum toxin, fillers, and thread lifts, are even more at the forefront of the advancement in aesthetics. Combining autologous therapies with traditional noninvasive methods can ultimately provide patients with more effective rejuvenation options.

Effects of L-PRF and A-PRF+ on periodontal fibroblasts in in vitro wound healing experiments

Objective

To determine whether leukocyte‐platelet‐rich fibrin (L‐PRF) and advanced platelet‐rich fibrin (A‐PRF+) differ in their in vitro capacity to induce proliferation and migration of periodontal fibroblasts.

Background

L‐PRF and A‐PRF + are autologous materials used in periodontal regenerative surgery. They derive from blood from patients, but have different characteristics. The literature is controversial regarding the effects of the two PRF preparations on periodontal tissue fibroblasts.

Materials and methods

L‐PRF and A‐PRF + membranes were prepared from eight patients and incubated in 3 mL of culture medium for 2 days. Gingival fibroblasts (G‐F) and periodontal ligament fibroblast (PDL‐F) primary cells were retrieved from 7 donors. These cells were pre‐cultured for 1 day in wound healing experiment plates leaving a gap of 500 ± 50 µm in a concentration of 3.3 x 10⁵ cells/mL. 70 µL of the cell suspension was placed in each half of the well. Thereafter, the pre‐cultured L‐PRF and A‐PRF + supernatants were added to the experimental plates, and the fibroblasts were incubated for another 24 h. Medium alone (NEG) and fibroblast growth factor II (FGF) were used as controls. Subsequently, cell migration was registered for 24 h with live cell imaging in a time frame microscope at 5% CO₂ in air at 37°C. Images were analyzed using ImageJ. Cell proliferation and cell viability were measured.

Results

L‐PRF and A‐PRF + induced higher cell proliferation than FGF and NEG. Both A‐PRF + and L‐PRF induced significant faster artificial wound closure than controls. Both PRF conditioned media induced faster cell migration in the initial phase (P < .01), but in the stoppage phase, the induced migration was higher for the A‐PRF+, compared with L‐PRF (P < .01).

Conclusion

L‐PRF and A‐PRF + have a stimulatory effect on migration and proliferation of periodontal fibroblasts, and artificial wound closure was longer sustained by A‐PRF + than L‐PRF.

The Role of Platelet Concentrates in Facial Fat Grafting

Autologous fat grafting is increasingly being used as a method for the repair of facial soft tissue defects and facial rejuvenation, given its low risk of adverse effects and high efficacy. However, the unpredictability of graft retention is a limitation of this procedure. In addition, there is no standard procedure to date for autologous fat grafting. Different methods have been developed to increase the retention of grafted fat. For instance, platelet concentrates have been used to directly deliver bioactive factors to grafted fat. Platelet concentrates also provide incidental therapeutic benefits by enhancing the persistence of fat grafted in the face via the release of growth factors and cytokines. In this review, we describe current strategies for improving the survival of facial fat grafts, mainly focusing on the application of growth factors/cytokines and platelet concentrates to fat grafting.

Advanced platelet-rich fibrin and freeze-dried bone allograft for ridge preservation: A randomized controlled clinical trial

BACKGROUND

Advanced platelet-rich fibrin (A-PRF) is an autogenous blood product with applications in dento-alveolar surgery. However, there is minimal information regarding its optimal clinical application or efficacy. The aim of this multi-arm parallel randomized controlled clinical trial was to evaluate the efficacy of A-PRF alone or with freeze-dried bone allograft (FDBA) in improving vital bone formation and alveolar dimensional stability during ridge preservation.

METHODS

Forty patients requiring extraction of non-molar teeth and replacement with dental implants were randomized into one of four ridge preservation approaches: A-PRF, A-PRF+FDBA, FDBA, or blood clot. A-PRF was prepared at 1,300 rpm for 8 minutes. Non-traumatic extractions and ridge preservation was performed. After an average of 15 weeks healing, bone core samples were harvested at the time of implant placement for micro-CT and histomorphometric analysis. Ridge dimensions were measured immediately after extraction and before implant placement.

RESULTS

Significantly greater loss of ridge height was noted in the blood clot group (3.8 ± 2.0 mm) compared to A-PRF (1.8 ± 2.1 mm) and A-PRF+FDBA (1.0 ± 2.3 mm) groups (P < 0.05). No significant differences in ridge width reduction were noted between groups. Significantly more vital bone was present in the A-PRF group (46% ± 18%) compared to the FDBA group (29% ± 14%) (P < 0.05). Bone mineral density was significantly greater in the FDBA group (551 ± 58 mg/cm³ ) compared to blood clot (487 ± 64 mg/cm³ ) (P < 0.05).

CONCLUSIONS

This study demonstrates A-PRF alone or augmented with FDBA is a suitable biomaterial for ridge preservation. This study represents the first randomized controlled clinical trial comparing A-PRF with and without FDBA to FDBA alone for ridge preservation.

Evaluation of New Bone Formation in Sinus Floor Augmentation With Injectable Platelet-Rich Fibrin-Soaked Collagen Plug: A Pilot Study

INTRODUCTION

The objective of this study is to evaluate the new bone formation after sinus floor augmentation with collagen plugs used as carriers for injectable platelet-rich fibrin (i-PRF).

MATERIALS AND METHODS

Postoperative immediate and postoperative 6th month panoramic radiographies of patients treated between January 1, 2015, and February 1, 2018, with sinus floor augmentation using i-PRF-soaked collagen plugs were retrieved from the archives, and subantral bone heights of distal and mesial regions of simultaneously inserted implants were measured with a software program. Statistical analysis was performed to understand whether there is a significant change in new bone formation at 6th month follow-up control.

RESULTS

A total of 18 implants were inserted in 12 patients. There was significant new bone formation at 6th month follow-up radiography at mesial and distal regions of inserted implants (P < 0.05).

CONCLUSION

New bone was regenerated with i-PRF carried by collagen plugs in sinus floor augmentation.

From Platelet-Rich Plasma to Advanced Platelet-Rich Fibrin: Biological Achievements and Clinical Advances in Modern Surgery

In the past 20 years, the platelet concentrates have evolved from first-generation products, i.e., platelet-rich plasma (PRP) and plasma rich in growth factors to the second-generation products such as leukocyte-platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF). These autologous products with a higher leukocyte inclusion and flexible fibrin mesh act as a scaffold to increase cellular migration in the angiogenic, osteogenic, and antimicrobial potential of these biomaterials in tissue regeneration. In the second-generation platelet concentrates, the protocols are easier, cheaper, and faster with an entire physiological fibrin matrix, resulting in a tridimensional mesh, not as rigid as one of the first generations. This allows the slow release of molecules over a longer period of time and triggers the healing and regenerative process at the site of injury. The potential of A-PRF to mimic the physiology and immunology of wound healing is also due to the high concentration of growth factors released as follows: vascular endothelial growth factor, platelet-derived growth factor, transforming growth factor-β, and anti-inflammatory cytokines that stimulate tissue cicatrization, vessels formation, and bone cell proliferation and differentiation. Furthermore, the number of neutrophils and monocytes/macrophages is higher releasing important chemotactic molecules such as chemokine ligand-5 and eotaxin. Thus, L-PRF and A-PRF have been used, especially in implantology, periodontology, and maxillofacial surgery. Future clinical applications include tissue regeneration/grafts, ulcers/skin necrosis in the diabetic patient and others, plastic surgery, and even musculoskeletal lesions.

Potential effects of advanced platelet rich fibrin as a wound-healing accelerator in the management of alveolar osteitis: A randomized clinical trial

Aim

The aim of the present study was to determine whether the use of advanced platelet rich fibrin based on the low speed⁺ centrifugation concept (A-PRF⁺) might improve the pain management and healing of delayed wound healing among cases of alveolar osteitis following mandibular third molar extraction.

Materials and Methods

The patients (N = 40) with a complaint of alveolar osteitis following third molar extractions were divided into two groups: Group I (control; saline only); and Group II (use of A-PRF⁺). Pain was evaluated using the visual analogue scale (VAS). Soft tissue healing was assessed by the modified Index of Landry, Turnbull and Howley and bone density was assessed with the i-Dixel 2.1.8.2 software. Inter-group comparisons were analyzed by means of a student t-test and the Mann Whitney U test to identify group samples. Analysis of variance and the Friedman test were applied for repeated measurements. The Wilcoxon test and Bonferroni's test for multiple comparisons were conducted at the time-factor level. Yates Correction was used to compare qualitative data.

Results

In regard to pain, A-PRF⁺ application demonstrated rapidly and continually reduced pain intensity at each respective time in comparison to the control. Statistically, the healing rates of epithelium and hard tissue were significantly faster in the A-PRF⁺ application group (p: 0.000, P < 0.05).

Conclusions

The results show that A-PRF⁺ might represent an improved and accelerating therapeutic development for hard and soft tissue healing in management of alveolar osteitis that is also effective in reducing pain.

A Proof of the Low Speed Centrifugation Concept in Rodents: New Perspectives for In Vivo Research

IMPACT STATEMENT

This study evaluated for the first time the composition and bioactivity of platelet-rich fibrin (PRF) produced from small animal blood by reducing the initial blood volume needed for the preparation of PRF from 10 to 3 mL. The results showed that different preparation protocols of PRF produced using 3 mL of animal blood exhibit the same composition, properties, and bioactivity as PRF prepared using 10 mL human blood.

Effects of leukocyte- and platelet-rich fibrin associated or not with bovine bone graft on the healing of bone defects in rats with osteoporosis induced by ovariectomy

OBJECTIVE

To evaluate the healing of critical size defects (CSDs) in calvaria of rats with osteoporosis induced by ovariectomy and treated with leukocyte- and platelet-rich fibrin (L-PRF) associated or not with bovine bone graft (XENO).

MATERIAL AND METHODS

A total of 32 rats underwent a bilateral ovariectomy procedure. After 3 months, one 5 mm in diameter CSD was created in the middle of the calvaria of each animal. In group C, defect was filled with blood clot only. In PRF, XENO, and PRF-XENO groups, defects were filled with 0.1 ml of L-PRF, 0.1 ml of XENO, and a mixture of 0.1 ml of L-PRF plus 0.1 ml of XENO, respectively. L-PRF compressed clots were used to cover the defects in PRF and PRF-XENO groups. Animals were submitted to euthanasia at 30 postoperative days. Histomorphometric, microtomographic, and immunohistochemical analyses were performed.

RESULTS

PRF-XENO group presented greater amount of neoformed bone (NB) when compared with XENO group, as well as higher expression of vascular endothelial growth factor (VEGF), osteocalcin (OCN), and bone morphogenetic protein (BMP-2/4) (p < .05). PRF group presented increased amount of NB and higher expression of VEGF, OCN, BMP-2/4, and Runt-related transcription factor 2 (RUNX-2) when compared with group C (p < .05).

CONCLUSIONS

(a) The isolated use of L-PRF clot can improve bone neoformation in CSDs in rats with osteoporosis induced by ovariectomy, but seems to lead to decreased amount of bone neoformation when compared to the isolated use of XENO; (b) L-PRF potentiates the healing of XENO in rats with osteoporosis induced by ovariectomy.

Biomaterial-based bone regeneration and soft tissue management of the individualized 3D-titanium mesh: An alternative concept to autologous transplantation and flap mobilization

Three-dimensional augmentation in severely atrophic bone and after cancer resection is a challenging clinical indication that is mostly solved using autologous bone transplantation. The development of the digital technique along with the additive manufacturing and three-dimensional (3D) printing opened new avenues for reconstructive oral and maxillofacial surgery. Therefore, patient-specific titanium mesh is a novel means of stabilizing the augmentation region using particulate bone substitute materials (BSMs) combined with autologous bone as a minimally invasive concept. However, dehiscence is a frequently reported complication in this field. Therefore, the aim of the present case series was to introduce a biomaterial-based regenerative concept in terms of exposed open healing to overcome the dehiscence related to 3D-titanium meshes. Additionally, this case series presents a novel protocol using a combination of xenogeneic BSMs with an autologous blood concentrate system (platelet-rich fibrin [PRF]) and collagen matrices without any autologous transplantation. Seven patients with alveolar ridge atrophy with different etiologies (cancer resection, severe atrophy after tooth loss, aplasia, trauma, implant infections) were treated using the open-healing concept. Therefore, after 3D augmentation using the described biomaterials, the flap margins were approximated, and the gap between the flap margins was bridged using a collagen matrix loaded with liquid PRF that was then covered by either a PTFE-based membrane or sterile latex. No periosteum splitting was performed at any time point. After a healing period of 4-8 months, all patients received dental implants as virtually planned. Bone biopsies were performed during dental insertion for histological evaluation. The augmentation area displayed a vital and well-vascularized newly formed bone that incorporated the BSM granules to build a hybrid bone. Additionally, open healing resulted in newly formed soft tissue without any signs of scar formation or fibrosis. The regenerated soft tissue was used to build a new flap during implant insertion and showed good functional and aesthetic results after implant insertion. The open-healing concept of the regeneration of the soft tissue along with bone tissue to regenerate a harmonic implantation bed is a minimally invasive intervention without periosteum splitting or large flap mobilization. However, further controlled clinical studies are needed to evaluate this concept in a larger patient cohort to outline the potential clinical benefit.

Molecular and Cellular Aspects of Socket Healing in the Absence and Presence of Graft Materials and Autologous Platelet Concentrates: a Focused Review

OBJECTIVES

The present manuscript aims to critically detail the physiologic process of socket healing, in the absence or presence of grafting materials or platelet concentrates, addressing the associated molecular and cellular events that culminate in the restoration of the lost tissue architecture and functionality.

MATERIAL AND METHODS

An electronic search in the National Library of Medicine database MEDLINE through its online site PubMed and Web of Science from inception until May 2019 was conducted to identify articles concerning physiologic process of socket healing, in the absence or presence of grafting materials or platelet concentrates. The search was restricted to English language articles without time restriction. Additionally, a hand search was carried out in oral surgery, periodontology and dental implants related journals.

RESULTS

In total, 122 literature sources were obtained and reviewed. The detailed biological events, at the molecular and cellular level, that occur in the alveolus after tooth extraction and socket healing process modulated by grafting materials or autologous platelet concentrates were presented as two entities.

CONCLUSIONS

Tooth extraction initiates a convoluted set of orderly biological events in the alveolus, aiming wound closure and socket healing. The healing process comprises a wide range of events, regulated by the interplay of cytokines, chemokines and growth factors that determine cellular recruitment, proliferation and differentiation in the healing milieu, in a space- and time-dependent choreographic interplay. Additionally, the healing process may further be modulated by the implantation of grafting materials or autologous platelet concentrates within the tooth socket, aiming to enhance the regenerative outcome.

Antimicrobial effects of various platelet rich concentrates-vibes from in-vitro studies-a systematic review

Aim

The aim of the current review was to outline the existing information related to antimicrobial properties of various platelet concentrates, as experimented in various in-vitro studies.

Background

One of the most interesting recent landmarks in the field of biological therapy has been the discovery that platelets, in addition to being capable of releasing hundreds of proteins and growth factors, can also release immunomodulatory agents with antimicrobial activity. Several international research groups have reported antimicrobial activities in both human platelets and other types of platelet rich plasma preparations.

Review Result

This review was carried-out pursuing a systematic approach. An electronic search was conducted on MEDLINE and GOOGLE SCHOLAR databases using suitable search terminologies. It included preclinical studies which assessed the antimicrobial activity of Autologous Platelet Concentrates(APC).Ten in-vitro studies and one animal study, which investigated APC effects on various microorganisms, were included. Almost in all the included in-vitro studies, it was found that complete breakdown of microbial load could not be achieved by any of the APC preparations but there occurred a reduction in the growth of microorganisms. Thus APCs displayed a bacteriostatic rather than bacteriocidal activity.The only animal study included in this review which had both in-vitro and in-vivo evaluation, also showed reduction of infection caused by different microorganisms.

Conclusion

Although the precise mechanism of synergy with microbial pathogens needs further validation, platelet concentrates proved to have antimicrobial properties.

Effect of Liquid Platelet-rich Fibrin and Platelet-rich Plasma on the Regenerative Potential of Dental Pulp Cells Cultured under Inflammatory Conditions: A Comparative Analysis

INTRODUCTION

Platelet-rich plasma (PRP) has been widely used in regenerative dentistry for over 2 decades. Nevertheless, previous studies have shown that its growth factor content is released over a short time period, and the application of anticoagulants limits its regenerative potential. Therefore, a second-generation platelet concentrate (liquid platelet-rich fibrin [PRF]) was developed without the use of anticoagulants and with shorter centrifugation times. The purpose of the present study was to compare the cellular regenerative activity of human dental pulp cells (hDPCs) when cultured with either liquid PRF or traditional PRP.

METHODS

The regenerative potential of hDPCs isolated from healthy human third molars (18-22 years, n = 5) was investigated in both normal and inflammatorylike conditions (lipopolysaccharide [LPS]) and assessed for their potential for dentin repair. The effects of liquid PRF and PRP were assessed for cellular migration, proliferation, and odontoblastic differentiation using a transwell assay, scratch assay, proliferation assay, alkaline phosphatase assay, alizarin red staining, and real-time polymerase chain reaction for genes encoding collagen type 1 alpha 1, dentin sialophosphoprotein, and dentin matrix protein 1, respectively. The effects of both platelet concentrates were also assessed for their ability to influence nuclear translocation of nuclear factor kappa B (p65) by immunofluorescence, and reverse-transcription polymerase chain reaction for genes encoding interleukin-1β, tumor necrosis factor alpha, and nuclear factor kappa B (p65) during an inflammatory condition.

RESULTS

Both PRP and liquid PRF increased the migration and proliferation of hDPCs when compared with the control group, whereas liquid PRF showed a notable significant increase in migration when compared with PRP. Furthermore, liquid PRF induced significantly greater alkaline phosphatase activity, alizarin red staining, and a messenger RNA expression of genes encoding collagen type 1 alpha 1, dentin sialophosphoprotein, and dentin matrix protein 1 when compared with PRP. When hDPCs were cultured with LPS to stimulate an inflammatory environment, a marked decrease in dentin-related repair was observed. When liquid PRF was cultured within this inflammatory environment, the reduced regenerative potential in this LPS-produced environment was significantly and markedly improved, facilitating hDPC regeneration. The messenger RNA expression of inflammatory markers including tumor necrosis factor alpha, interleukin-1β, and p65 were all significantly decreased in the presence of liquid PRF, and, furthermore, liquid PRF also inhibited the transport of p65 to the nucleus in hDPCs (suggesting a reduced inflammatory condition).

CONCLUSIONS

The findings from the present study suggest that liquid PRF promoted greater regeneration potential of hDPCs when compared with traditional PRP. Furthermore, liquid PRF also attenuated the inflammatory condition created by LPS and maintained a supportive regenerative ability for the stimulation of odontoblastic differentiation and reparative dentin in hDPCs.

A specific affinity cyclic peptide enhances the adhesion, expansion and proliferation of rat bone mesenchymal stem cells on β‑tricalcium phosphate scaffolds

Osteonecrosis of the femoral head (ONFH) is a common osteological disease. Treatment of ONFH prior to the collapse of the femoral head is critical for increasing therapeutic efficiency. Tissue engineering therapy using bone mesenchymal stem cells (BMSCs) combined with a scaffold is a promising strategy. However, it is currently unclear how to improve the efficiency of BMSC recruitment under such conditions. In the present study, a specific cyclic peptide for Sprague-Dawley rat BMSCs, CTTNPFSLC (known as C7), was used, which was identified via phage display technology. Its high affinity for BMSCs was demonstrated using flow cytometry and fluorescence staining. Subsequently, the cyclic peptide was placed on β-tricalcium phosphate (β-TCP) scaffolds using absorption and freeze-drying processes. Adhesion, expansion and proliferation of BMSCs was investigated in vitro on the C7-treated β-TCP scaffolds and compared with pure β-TCP scaffolds. The results revealed that C7 had a promoting effect on the adhesion, expansion and proliferation of BMSCs on β-TCP scaffolds. Therefore, C7 may be effective in future tissue engineering therapy for ONFH.

Hard and Soft Tissue Evaluation of Different Socket Preservation Procedures Using Leukocyte and Platelet-Rich Fibrin: A Retrospective Clinical and Volumetric Analysis

PURPOSE

The extraction of a tooth is followed by hard and soft tissue changes that can compromise implant placement. The aim of the present retrospective study was to compare the clinical and radiographic outcomes of different ridge preservation procedures based on the use of leukocyte and platelet-rich fibrin (L-PRF).

MATERIALS AND METHODS

The study population consisted of all patients who had undergone surgery from January 1, 2017 to January 1, 2018 for alveolar ridge preservation on single posterior teeth using 3 clinical protocols: L-PRF alone, L-PRF mixed with a bone xenograft, and bone xenograft alone. Clinical and radiographic measures were recorded preoperatively and at 6 months postoperatively to determine the horizontal and vertical ridge resorption.

RESULTS

A total of 45 patients were included in the present study. All the surgeries were performed successfully, and no intraoperative complications developed. The L-PRF group experienced significantly greater horizontal and vertical bone resorption. The L-PRF plus bone xenograft group had less vertical and horizontal bone resorption than the bone xenograft alone group. Statistically significant differences in postoperative pain and wound healing were observed, with the bone xenograft alone group, in particular, having higher values for pain and experiencing delayed wound healing.

CONCLUSIONS

Within the limitations of the present retrospective study, the use of a bone xenograft alone or L-PRF combined with a bone xenograft to perform alveolar ridge preservation procedures significantly limited bone resorption.

Platelet-Rich Fibrin and its Emerging Therapeutic Benefits for Musculoskeletal Injury Treatment

New therapies that accelerate musculoskeletal tissue recovery are highly desirable. Platelet-rich fibrin (PRF) is a leukocyte- and platelet-rich fibrin biomaterial that acts as a binding site for both platelets and growth factors. Through increasing the local concentration of growth factors at specific tissues, PRF promotes tissue regeneration. PRF has been frequently used in combination with bone graft materials to reduce healing times and promote bone regeneration during maxillofacial surgery. However, its benefits during muscle repair and recovery are less well-documented. Here, we perform a narrative review on PRF therapies and muscle injuries to ascertain its beneficial effects. We reviewed the factors that contribute to the biological activity of PRF and the published pre-clinical and clinical evidence to support its emerging use in musculoskeletal therapy. We include in vitro studies, in vivo animal studies and clinical articles highlighting both the success and failures of PRF treatment. PRF can promote the healing process when used in a range of orthopaedic and sports-related injuries. These include cartilage repair, rotator cuff surgery and anterior cruciate ligament surgery. However, conflicting data for these benefits have been reported, most likely due to inconsistencies in both PRF preparation protocols and dosing regimens. Despite this, the literature generally supports the use of PRF as a beneficial adjuvant for a range of chronic muscle, tendon, bone or other soft tissue injuries. Further clinical trials to confirm these benefits require consistency in PRF preparation and the classification of a successful clinical outcome to fully harness its potential.

Leucocyte- and platelet-rich fibrin as a rescue therapy for small-to-medium-sized complex wounds of the lower extremities

BACKGROUND

Generally, advanced wound care resources are applied for complex wounds that pose a challenge to the medical and nursing teams. In this report, the use of leukocyte- and platelet-rich fibrin (L-PRF) is emphasized for complex wounds as an alternative, simple, inexpensive, time-saving process that does not require hospitalization and has a healing potential over that of bare soft tissue, including bone, tendon, and ligaments. The aim of this study is to extend the use of L-PRF in small-to-moderate-sized complex wounds of lower extremities in which L-PRF maintains the sensitive structures viable.

METHODS

Between January 2016 and December 2017, 17 small-to-moderate-sized complex wounds of lower extremities treated with L-PRF were recruited from the plastic and reconstructive surgery clinic in Aydin State Hospital, Turkey. The treatment was administered twice per week in the outpatient clinic. Depending on the size and extension of the complex wound, two to five blood samples were collected into 8.5 ml dry, glass vacuum tubes with no anticoagulant, and samples were immediately centrifuged at 1630×g for 5 min to obtain L-PRF. Complete healing was defined as the day of complete wound epithelialization.

RESULTS

The median values of the initial wound size and wound duration were 12 cm2 (interquartile range, 6 to 23 cm2) and 8 months before first admission (interquartile range, 4 to 18 months), respectively. All wounds showed significant improvements after L-PRF therapy and full closure after a median of 18 months, with an interquartile range of 11 to 34 months of L-PRF applications. There were recurrences of wounds during the first 6 months after therapy. No adverse events were observed.

CONCLUSIONS

Our results add to the growing evidence that L-PRF treatments protect and maintain bare soft tissue structures viable, facilitate the formation of granulation tissue and epithelization, and remarkably reduce the need for additional soft tissue surgeries in small-to-medium-sized complex wounds.

Comparison of the effect of advanced platelet-rich fibrin and leukocyte- and platelet-rich fibrin on outcomes after removal of impacted mandibular third molar: A randomized split-mouth study

Aim

In this study, it was aimed to investigate and compare the postoperative effects of leukocyte- and platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF) in terms of pain, swelling, and trismus after mandibular third molar surgery.

Subjects and Methods

The study included a total of 27 patients with bilateral impacted mandibular third molar, which surgically operated at different times. Patients were evaluated in two randomly separated groups. For the first and second group, A-PRF and L-PRF were applied into the tooth socket, respectively. The outcome variables were pain, swelling, the number of analgesics taken, and trismus. These variables were also assessed based on first, second, third, and seventh days following the operation.

Statistical Analysis Used

The data were collected and analyzed with unpaired Student's t-test and Mann-Whitney U test.

Results

The study was conducted with 27 patients, consisting of 15 females and 12 males between ages of 18-26. The visual analog scale pain scores of the L-PRF group during first (P < 0.05), second, and third days and total values (P < 0.01); the number of analgesics on days 2 (P < 0.01) and 3; and their total values (P < 0.05) were significantly higher than the A-PRF group. There was no significant difference between swelling, trismus, and the duration of operation (P > 0.05).

Conclusion

The results of this study showed that the use of A-PRF after mandibular third molar extraction significantly reduces postoperative pain and the patients need to take analgesics of A-PRF group compared to L-PRF group.

Antimicrobial and antibiofilm potential of injectable platelet rich fibrin-a second-generation platelet concentrate-against biofilm producing oral staphylococcus isolates

Injectable Platelet rich fibrin (i-PRF) is a platelet concentrate that has been extensively used for multiple medical purposes and is a valuable adjunct for the regeneration of damaged tissues in surgical procedures. The enriched bioactive substances in i-PRF are responsible for speeding the wound healing process. Infection of biofilm producing bacteria in surgical wounds is becoming a serious threat. Research in this field is focused on new strategies to fight infections and to reduce the healing time. The present study was aimed to evaluate the in vitro antimicrobial and antibiofilm effects of i-PRF against oral pathogenic biofilm producing staphylococcus bacteria isolated from patient with dental and oral abscess. The antibacterial activity of i-PRF, was determined through broth microdilution as minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). i-PRF exhibited bactericidal activity against both non biofilm and biofilm producing bacteria. i-PRF could be potential antimicrobial peptide used to combat postoperative infections caused by biofilm producing staphylococcus.

Platelet-Rich Fibrin Scaffolds for Cartilage and Tendon Regenerative Medicine: From Bench to Bedside

Nowadays, research in Tissue Engineering and Regenerative Medicine is focusing on the identification of instructive scaffolds to address the requirements of both clinicians and patients to achieve prompt and adequate healing in case of injury. Among biomaterials, hemocomponents, and in particular Platelet-rich Fibrin matrices, have aroused widespread interest, acting as delivery platforms for growth factors, cytokines and immune/stem-like cells for immunomodulation; their autologous origin and ready availability are also noteworthy aspects, as safety- and cost-related factors and practical aspects make it possible to shorten surgical interventions. In fact, several authors have focused on the use of Platelet-rich Fibrin in cartilage and tendon tissue engineering, reporting an increasing number of in vitro, pre-clinical and clinical studies. This narrative review attempts to compare the relevant advances in the field, with particular reference being made to the regenerative role of platelet-derived growth factors, as well as the main pre-clinical and clinical research on Platelet-rich Fibrin in chondrogenesis and tenogenesis, thereby providing a basis for critical revision of the topic.

Development of a novel histological and histomorphometric evaluation protocol for a standardized description of the mid-palatal suture - An ex vivo study

The hard palate and mid-palatal suture are highly important for orthodontic treatment. In cases of transverse maxillary deficiency, palatal expansion is the treatment of choice. As nowadays a growing number of adult patients receive orthodontic treatment, an understanding of suture development throughout life is important to derive tailored orthodontic treatment techniques for each age group. Histological, histochemical and immunohistochemical stains (haematoxylin & eosin, Azan, Movat pentachrome, Masson-Goldner trichrome, Sirius Red, CD 31, osteopontin and TRAP) and histomorphometric analyses were re-established to detect the structural conditions of the mid-palatal suture in human cadavers of three different age groups (20-39, 40-59 and 60-80 years). The mid-palatal suture of the selected age groups (total of n = 12; n = 4 in every group m = f) exhibited marked differences in sutural morphology and metabolism. A wide, interdigitated and well-vascularized suture was observed in younger specimens compared with straighter and smaller sutures with fewer vessels and lower bone density in the 60-80 year group. The fibre composition within the sutural gap differed between the three age groups. Delicate fibres were found in the 20-39 year group, and a tightly interwoven 3D fibre-network was observed in the 40-59 year group. Atrophy primarily characterized the fibres in the 60-80 year group. This evidence demonstrates differences between the evaluated groups. These results suggest that the staining methods used are suitable for the description and evaluation of the morphology and metabolism of mid-palatal sutures. Further investigation is necessary to provide an in-depth description of sutural maturation over a lifetime.

Influence of Fractionation Methods on Physical and Biological Properties of Injectable Platelet-Rich Fibrin: An Exploratory Study

Injectable platelet-rich fibrin (i-PRF) has been used as an autografting material to enhance bone regeneration through intrinsic growth factors. However, fractionation protocols used to prepare i-PRF can be varied and the effects of different fractionation protocols are not known. In this study, we investigated the influence of different fractions of i-PRF on the physical and biological properties derived from variations in i-PRF fractionation preparation. The i-PRF samples, obtained from the blood samples of 10 donors, were used to harvest i-PRF and were fractioned into two types. The yellow i-PRF fractionation was harvested from the upper yellow zone, while the red i-PRF fractionation was collected from both the yellow and red zone of the buffy coat. The viscoelastic property measurements, including the clot formation time, α-angle, and maximum clot firmness, were performed by rotational thromboelastometry. The fibrin network was examined using a scanning electron microscope. Furthermore, the concentration of growth factors released, including VEGF, TGF-β1, and PDGF, were quantified using ELISA. A paired t-test with a 95% confidence interval was used. All three viscoelastic properties were statistically significantly higher in the yellow i-PRF compared to the red i-PRF. The scanning electron microscope reviewed more cellular components in the red i-PRF compared to the yellow i-PRF. In addition, the fibrin network of the yellow i-PRF showed a higher density than that in the red i-PRF. There was no statistically significant difference between the concentration of VEGF and TGF-β1. However, at Day 7 and Day 14 PDGF concentrations were statistically significantly higher in the red i-PRF compared to the yellow group. In conclusion, these results showed that the red i-PRF provided better biological properties through the release of growth factors. On the other hand, the yellow i-PRF had greater viscoelastic physical properties. Further investigations into the appropriate i-PRF fractionation for certain surgical procedures are therefore necessary to clarify the suitability for each fraction for different types of regenerative therapy.

Standardization of relative centrifugal forces in studies related to platelet-rich fibrin

Platelet-rich fibrin (PRF), a second-generation platelet concentrate, has been the focus of intensive research endeavors over the past 2 decades. Over the years, however, numerous reports have inaccurately reported relative centrifugal force (RCF) values, which has caused considerable confusion in the field. Furthermore, the use of trade names such as leukocyte and platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF) has further confused many readers, since studies have not always used centrifugation parameters with equal rotor sizes, angulation of tubes, and/or tube design. This has led to considerable misperception in the report of relative centrifugal force. Herein is described necessary parameters pivotal for the future report of RCF in studies related to PRF, which include: 1) dimensions of the rotor (radius at the clot and end of the tube); 2) rotor angulation for the tube holder; 3) revolutions per minute (RPM) and time; 4) RCF value calculated at either the RCF-minimum, RCF-clot, or RCF-maximum; 5) composition and size of tubes used to produce PRF; and 6) centrifugation model used. This editorial aims to minimize confusion in the field and create more transparent research reporting RCF values in future studies.

Additive effectiveness of autologous platelet-rich fibrin in the treatment of intrabony defects: A PRISMA-compliant meta-analysis

BACKGROUND

This meta-analysis was performed to determine the additive effectiveness of autologous platelet-rich fibrin in the treatment of intrabony defects in chronic periodontitis patients.

METHODS

Pertinent studies were identified by a search in Medline, EMBASE, the Web of Science, and the Cochrane Library. The trials searched were evaluated for eligibility. Cochrane Collaboration's Review Manager software was used to perform the meta-analyses.

RESULTS

Twelve eligible clinical trials were included. Pooled data found that adjunctive platelet-rich fibrin exactly yielded a significantly superior probing depth reduction compared with open flap debridement alone (weighted mean difference, 1.01; 95% confidence interval 0.95-1.08; P < .00001). The clinical attachment level (CAL) gain after treatment for 9 months was higher in patients treated with platelet-rich fibrin plus open flap debridement group than in open flap debridement-treated patients (weighted mean difference, 1.29; 95% confidence interval 0.96- 1.61; P < .00001). Similarly, the meta-analysis demonstrated that platelet-rich fibrin was superior to single open flap debridement with respect to gingival marginal level change (weighted mean difference, 0.45; 95% confidence interval 0.31-0.58; P < .00001). Regarding the hard tissue radiographic parameters, including defect depth reduction and percentage of fill defects in bone, adjunctive platelet-rich fibrin yielded significantly superior results compared with open flap debridement alone.

CONCLUSION

Adjunctive use of platelet-rich fibrin with open flap debridement significantly improves fill defects when compared to open flap debridement alone. However, additional powered studies with much larger sample sizes are needed to obtain a more concrete conclusion.

[Study on the bone regeneration induced by advanced-platelet-rich fibrin and β- tricalcium phosphate composite]

Objective

To explore the osteogenesis effect of advanced-platelet-rich fibrin (A-PRF) and β-tricalcium phosphate (β-TCP) composite.

Methods

Thirty-two healthy female New Zealand rabbits were randomly selected. A-PRF was prepared by collecting blood from middle auricular artery. Rabbits were randomly divided into 6 groups: groups A, B, C, D, and E (6 rabbits in each group) and group F (2 rabbits). Bone defects (6 mm in diameter, 8 mm in depth) were drilled into femur condyle of each rabbit's both back legs. Then A-PRF and β-TCP composites manufactured by different proportion were planted into bone defects of group A (1∶1), group B (2∶1), group C (4∶1), group D (1∶2) and group E (1∶4) ( V/ V). The bone defect was not repaired in group F. The specimens were collected at 8 and at 12 weeks after operation. Then gross observation, X-ray examination, Micro-CT examination, and biomechanical test were performed. The bone volume/total volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp), compressive strength, and modulus of elasticity were calculated.

Results

The gross observation and X-ray examination showed that the osteogenesis effect at 12 weeks was better than that at 8 weeks. At the same time point, the repair of bone defect and the formation of new bone in group B were better than those in other groups. Micro-CT examination showed that the trabeculae of new bone in group B were the most and the trabeculae arranged closely at 8 and 12 weeks. Besides there were significant differences in BV/TV, Tb.N, and Tb.Sp between group B and the other groups ( P<0.05). There were significant differences in Tb.N and Tb.Th in group B, BV/TV and Tb.Sp in group C, Tb.Sp in group D between 8 weeks and 12 weeks ( P<0.05). Biomechanical tests showed that the compression strength and elastic modulus of group B were the highest, and the compression strength and elastic modulus of group C were the lowest at 8 and at 12 weeks, showing significant differences ( P<0.05). There were significant differences in compression strength and elastic modulus of each group between 8 weeks and 12 weeks ( P<0.05).

Conclusion

The A-PRF and β-TCP composite can repair femoral condylar defects in rabbits, and the osteogenesis is better in proportion of 2∶1.

Effect of advanced platelet-rich fibrin on accelerating alveolar bone formation in dogs: a histological and immunofluorescence evaluation

Several methods have been developed to regenerate lost alveolar bone. Platelet-rich fibrin (PRF) is a useful adjunct for new bone formation in dentistry. To elucidate the effect of advanced PRF (A-PRF) on bone formation, we inserted A-PRF clots in sockets after tooth extraction. Premolars were extracted from beagle dogs, and A-PRF was applied to the socket. New bone formation was assessed using histological and immunofluorescence examinations, and the bone formation ratio was evaluated 14 and 30 days postoperatively. Histological examination revealed newly formed bone filling the sockets up to the center in the A-PRF group at 14 days postoperatively, while thick and regular bone trabeculae were arranged in porous bone after 30 days. Higher expressions of osteocalcin and osteopontin were observed in newly formed bone in the A-PRF group, compared to the control group. The bone formation ratio was also higher in the A-PRF group than in the control group. Thus, A-PRF application may result in enhanced new bone formation and may aid in accelerating bone formation. A-PRF was more rapid than a self-limiting process during induction of bone formation by enhancing osteoblast activity and may be useful for bone formation in clinical medicine.

The Application of Three-Dimensional Printing Model and Platelet-Rich Fibrin Technology in Guided Tissue Regeneration Surgery for Severe Bone Defects

A 36-year-old male patient diagnosed with severe chronic periodontitis was treated with novel surgery for his maxillary right lateral incisor. Preoperatively, a 3D printer was used, based on CBCT datasets, to produce a photosensitive resin bony anatomy replica. The patient's blood was centrifuged to obtain advanced platelet-rich fibrin (A-PRF) and injected platelet-rich fibrin (I-PRF), then mixed with Bio-Oss and packed onto the 3D replica to form the ideal shape. The replica was positioned at the planned sites without changes. The A-PRF membrane was applied over the replica as well as a Bio-Gide collagen membrane. Fifteen months after the surgery, clinical and radiographic followup revealed greatly reduced pocket depths and significant 3D alveolar bone fill at the treatment site. Based on these short-term results, the initial 3D printing surgical temple assisted guided tissue regeneration method resulted in significant clinical and radiographic improvements; A-PRF/I-PRF should be considered an ideal biomaterial for regenerative periodontal therapy.

Platelet-rich fibrin as an alternative adjunct to tendon-exposed wound healing: A randomized controlled clinical trial

BACKGROUND

The use of platelet-rich fibrin (PRF) has attracted great interest in the treatment of oral and maxillofacial procedures, gingival recessions, and bone healing. However, PRF has been reported hardly to prepare wound bed before skin grafting. This randomized clinical study sought to identify the effect of PRF as an alternative adjunct to tendon-exposed wound healing.

METHODS

Thirty-six patients with tendon-exposed wounds were treated by applying Integra or PRF (n=18 per group). The take rate of Integra or PRF and pain levels assessed with the four-point verbal rating scale (VRS-4) for the first 5days after application were measured for each condition. Data of texture change analysis were assessed and recorded for a duration of 3 months postoperatively.

RESULTS

The take rate was less in the Integra group than in the PRF group (92.39 vs 97.83 P<0.001). After surgery, compared to the Integra group, the patients in the PRF group reported significantly lower pain scores (P<0.001). Texture changes from the Integra group were rated higher than those from the PRF (P<0.001).

CONCLUSION

The use of PRF could be an option for tendon exposed areas where the wound is unfit for standard skin grafting or flap transfer.

Injectable-Platelet-Rich Fibrin-Smart Blood with Stem Cells for the Treatment of Alopecia: A Report of Three Patients

Hair loss or alopecia in males is very common, and so is its treatment. Until now, platelet-rich plasma has been in use for hair regeneration, which has shown results but lacks regenerative potential as compared to platelet-rich fibrin (PRF). Injectable-PRF (i-PRF) is advanced version of PRF in liquid form which can be injected and contains stem cells with high regenerative potential. Hair regeneration in Type VI and Type VII was observed which are difficult to treat. Hair growth with i-PRF has better regenerative potential. All cases reported showed improvement in hair growth.

Fabrication, modeling and optimization of lyophilized advanced platelet rich fibrin in combination with collagen-chitosan as a guided bone regeneration membrane

In this study, lyophilized advanced platelet rich fibrin (A-PRF) was used in combination with collagen-chitosan membrane for the first time to combine advantages of both collagen and A-PRF membranes. Response surface methodology (RSM) was used to design the experimental condition and to correlate the effects of parameters, including chitosan/collagen (chit/col) weight ratio and A-PRF concentration on Young's modulus, mesenchymal stem cell (MSCs) viability and degradation rate of the membranes. Results showed that Young's modulus of the membranes was intensified by increasing chit/col weight ratio and decreasing A-PRF concentration from 3 to 8 MPa. Cell viability of MSCs was improved by both increasing chit/col weight ratio and A-PRF concentration. Moreover, as chit/col weight ratio increased from 0 to 4 and A-PRF concentration decreased from 5 to 0, degradation rate of the membranes decreased from 90 to 20% after four weeks incubation. Finally, based on Design Expert Software calculation for minimizing the degradation rate and maximizing both Young's modulus and cell viability, the values of chit/col weight ratio and A-PRF concentration were suggested to be 4 and 0.58 mg/ml, respectively. Alkaline phosphatase (ALP) activity analysis showed that the addition of A-PRF caused higher osteogenic differentiation.

Fifteen Years of Platelet Rich Fibrin in Dentistry and Oromaxillofacial Surgery: How High is the Level of Scientific Evidence?

Platelet-rich fibrin is a blood concentrate system used for soft tissue and bone tissue regeneration. In the last decade, platelet rich fibrin (PRF) has been widely used in different indication fields, particularly in oral and maxillofacial surgery. This review investigates the level of scientific evidence of published articles related to the use of PRF for bone and soft tissue regeneration in dentistry and maxillofacial surgery. An electronic literature research using the biomedical search engine “National Library of Medicine” (PubMed-MEDLINE) was performed in May 2017. A total of 392 articles were found, 72 of which were classified for each indication field. When comparing PRF with biomaterials vs biomaterial alone in sinus lift (5 studies; IIa), no statistically significant differences were detected. Socket preservation and ridge augmentation using PRF significantly enhanced new bone formation compared to healing without PRF (7 studies Ib, IIa, IIb). Reepithelialization and bone regeneration was achieved in 96 of 101 patients diagnosed with medication-related osteonecrosis of the jaw (5 studies, III). In periodontology, PRF alone (6 studies; Ib, IIa, IIb) or its combination with biomaterials (6 studies; Ib, IIa, IIb) significantly improved the pocket depth and attachment loss compared to a treatment without PRF. Over 70% of the patients were part of studies with a high level of scientific evidence (randomized and controlled prospective studies). This published evidence (38 articles), with a high scientific level, showed that PRF is a beneficial tool that significantly improves bone and soft tissue regeneration. However, the clinical community requires a standardization of PRF protocols to further examine the benefit of PRF in bone and soft tissue regeneration in reproducible studies, with a higher scientific level of evidence.